JPH05333650A - Method for detecting amount of sticking toner and method for forming image - Google Patents

Abstract

PURPOSE:To obtain an image in which color reproduction is kept satisfactory all the time by judging whether a multicolor image of desired color reproduction is obtained or not, and adjusting process conditions properly when it is not obtained. CONSTITUTION:When electrostatic latent images on a photosensitive drum 1 are developed by development units 3Y, 3M, and 3C in order, an amount of sticking toner of a toner image developed on the photosensitive drum 1 is detected for each color by a reflected density detecting means 90. When a first CPU 80a judges that the amount of sticking toner is smaller than the reference amount, a second CPU 80b controls the process conditions for forming the toner image so that the amount of sticking toner becomes proper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention employs a developing method for visualizing an electrostatic latent image by using a two-component developer consisting of toner and carrier, and records a color image of a plurality of colors. The present invention relates to a toner adhesion amount detection method that can easily determine whether desired color reproduction is performed, and an image forming method that performs processing based on the result of the detection method.

[0002]

2. Description of the Related Art A color image recording apparatus is generally equipped with a developing device for loading yellow, magenta, cyan and black developers. In this case, the difference in toner charge amount between the color developers is small when the color developers are first loaded in the developing device.

However, as a feature of the color image recording apparatus, the developing sleeve and the agitating means in the developing device are continuously driven to rotate for simplification of control, and each color developer is not necessarily consumed uniformly. However, since the amount of consumption differs for each color, the stirring time of each color developer existing in the developing device varies as the copying is continued. Therefore, a difference in toner charge amount occurs between the color developers. This difference in charge amount adversely affects the developability.

That is, the developing property is a force (developing force) obtained by subtracting the adhesive force between the toner and the carrier (Coulomb force) and the adhesive force between the developing sleeve and the developer from the force caused by the electric field due to the electrostatic latent image. caused by.

It should be noted here that the Coulomb force tends to increase greatly as the toner charge amount Q / m increases in comparison with other forces.

Therefore, an increase in the toner charge amount appears as a decrease in developing power, and a decrease in the toner charge amount appears as an increase in developing power. Due to the difference in the toner charge amount between the color developers, a desired toner adhesion amount for each color cannot be obtained during multicolor reproduction, which causes a problem that the color balance of the reproduced image is lost.

On the other hand, some color image recording apparatuses employ an image forming process (hereinafter referred to as a KNC process) in which toner images of a plurality of colors are superposed on a photoconductor to form a toner image of a plurality of layers. ..

The KNC process charges on one photoreceptor,
By repeating image exposure and development processes for a plurality of colors, toner images of a plurality of layers and a plurality of colors are formed on the photoconductor.

The charging, image exposure and development processes are
In the case of a cycle, when recharged after the second cycle, the potential after image exposure fluctuates due to the toner layer on the photosensitive drum formed in the previous cycle. This is because the exposure light is scattered on the surface of the toner particles or reflected at the interface of the toner particle clusters and does not reach the surface of the photosensitive drum below the toner layer. As a result, in the image exposure process, the surface potential of the photosensitive drum causes a potential difference between the toner adhering portion and the toner non-adhering portion, which causes a problem that the hue and the density are changed in the second and subsequent developing processes.

Therefore, in consideration of the relationship between the toner charge amount and the toner adhesion amount of each color described above, when the KNC process is adopted, a desired toner adhesion amount cannot be obtained. There is a problem that becomes unstable.

[0011]

On the other hand, in the conventional detection of the toner adhesion amount, a reference toner image is individually formed with a plurality of color toners and the toner adhesion amount for each color is detected. It was However, this can only determine whether the image forming condition of one color toner is normal or abnormal, and when a multicolor image is formed by superposing a plurality of color toners, the toner of a certain color When all the colors are normal or all the colors are not abnormal such that the amount is normal and the other toner amounts are abnormal, the toner image forming conditions cannot be correctly determined.

Further, since the detection is performed by using a plurality of sensors or exchanging the filter, the apparatus becomes complicated and it is difficult to dispose the sensor around the photosensitive member.

Further, since the respective reference toner images are formed at different positions on the photosensitive drum, the latent image forming condition is not constant,
The accuracy of the toner adhesion amount detection was lowered.

Furthermore, when a plurality of light emitting elements and light receiving elements are used, it is necessary to adjust variations in the amount of emitted light and the spectral sensitivity characteristics, which requires time and effort for adjustment and lowers accuracy.

The present invention solves the above-mentioned problems, and a color reproduction judging method capable of easily judging whether or not desired color reproduction is performed for a multicolor image in which toners of a plurality of colors are superposed. The purpose is to provide.

It is another object of the present invention to provide an image forming method in which, when desired color reproduction has not been performed, adjustment is performed so that proper process conditions are achieved, and good color reproduction is always maintained.

[0017]

In order to achieve the above object, the present invention develops a plurality of reference latent images formed at the same position on a photosensitive member with color toners of different colors sequentially to obtain a plurality of color toners. When forming a reference color toner image with
Each time one color toner is developed, the amount of adhered color toner is detected by the detection means, and this detection is performed a plurality of times to determine whether the amount of adhered toner is normal or abnormal.

According to the present invention, the toner adhesion amount detection result is
Allow normal image process execution if normal

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of an image recording apparatus to which the toner amount detecting method of the present invention is applied.

The structure of the image recording apparatus 100 of this embodiment will be described below.

The image recording apparatus 100 includes a latent image carrier 1, a charger 2, a motor driver 10, an encoder 11, developing devices 3Y, 3M, 3C, 3BK, a developing bias circuit 32, and a toner density detecting means 31Y (see FIG. 2). ), 31M, 31
C, 31BK, transfer device 4, cleaning device 5, high-voltage power supply circuit 30, microcomputers 80a, 80b, reflection density detection means 90, reading optical system 51, scanning optical system 5
2 and a reading / scanning optical system drive circuit 53. When a copy button (not shown) is pressed, the microcomputer 8
On the basis of the timing signal from 0a, the scanning optical system 52 emits a light source with an image signal corresponding to the image density of the original image to irradiate the latent image carrier 1 with light, and the surface of the photoreceptor of the latent image carrier 1 is statically illuminated. An electrostatic latent image is formed, and the electrostatic latent image formed on the surface of the latent image carrier 1 is developed by developing devices 3Y, 3M, 3C, 3BK to visualize as a multicolor toner image, and based on the resist signal. By driving the transfer device 4 to discharge, the toner image is transferred onto a transfer sheet. After that, the transfer paper is fixed to form a reproducible image that can be stored.

As the latent image carrier 1, a drum-shaped conductive indicator made of aluminum having a diameter of 150 mm is used, and an ethylene vinyl acetate copolymer having a thickness of 0.1 μm is formed on the indicator.
O formed by providing a photosensitive layer having a film thickness of 35 μm on the intermediate layer
PC photoconductor (hereinafter referred to as photoconductor drum),
When the photosensitive layer is irradiated with light, the surface potential decreases. Therefore, if the photosensitive drum is previously uniformly charged to a predetermined potential and then is irradiated with light based on the density of the original image, the surface potential of the photosensitive drum becomes non-uniform, and a portion having a lowered potential can be formed. This is a so-called electrostatic latent image. The latent image carrier 1 is not limited to this, and may have another structure such as a photoconductor made of amorphous silicon. The latent image carrier 1 is not limited to a drum shape, but may be a belt shape. Here, a drum-shaped photosensitive member made of OPC will be described.

The motor driver 10 mainly comprises the photosensitive drum 1.
It is a circuit for driving and controlling a main motor (not shown) for rotating the main motor, and controls the number of rotations and the rotation of the main motor based on a control signal from the microcomputer 80a. The encoder 11 generates a pulse signal having a predetermined width corresponding to the rotation phase of the photosensitive drum 1. As a result, the microcomputer 80a detects the rotation phase of the photosensitive drum 1.

Developing units 3Y (see FIG. 2), 3M, 3C, 3
BK has the same mechanical structure except that the components of the developer to be loaded are different. Therefore, the developing device 3Y will be described as a representative.

The developing device 3Y includes a sleeve 42 containing a magnet roller 41 having N and S poles in the developing layer, and first and second screw-shaped agitating rollers 44 and 45.
Regulation member 43 for regulating the layer thickness of the developer on the sleeve 42
Is equipped with.

The first stirring member has a shape that conveys the developer toward the front side of the recording paper, and the second stirring member has a shape that conveys the developer toward the back side of the recording paper. Further, the developing device is provided with a partition wall between the first and second stirring members so that the developer is smoothly circulated and is not locally retained.

The scraper 46 is provided in the form of a rotatable roller so as to come into pressure contact with the sleeve, and scrapes the developer, which has passed through the developing area and has consumed toner, from the sleeve. As a result, the developer conveyed to the developing area can be replaced, and the developing conditions are stabilized.

The sleeve 42 is provided with a developing bias circuit 32 for applying a voltage having a DC bias component via a protective resistance to adhere toner according to an electrostatic latent image and prevent fogging on the background. There is.

The developing bias circuit 32 includes an AC power source for applying an AC bias for causing the toner to vibrate between the sleeve and the photosensitive drum 1 in the developing area, and a high voltage DC power source for applying a DC bias. Development bias circuit 32
Is the developing bias V according to the control signal from the CPU 80b.
_B can be changed to three stages V _B1 , V _B2 , and V _B3 .
In the present invention, since the reversal developing method is used, the developing bias V _B1 has a potential difference of about 150 (V) with respect to the initial charging potential V _H so that toner is attached according to the electrostatic latent image and fog is prevented. , Faithful development is performed. The developing bias V _B2 is the same as the initial charging potential V _H to enhance the developing power. The developing bias V _B3 has a potential that lowers the developing force in relation to the initial charging potential V _H.

Toner concentration detecting means 31Y, 31M, 31
C and 31BK are means for detecting a change in the transmittance of the developer, and are means for detecting the toner concentration in the developer loaded in the developers 3Y, 3M, 3C and 3BK. A means for detecting the volume level of the developer in 3M, 3C, 3BK may be used. Although not limited to these, here, for convenience of description, a toner concentration detecting unit that detects the toner concentration based on a change in transmittance will be described. As shown in FIG. 3, the toner concentration detecting means, for example, 31Y, is connected in parallel to a toner concentration detecting coil 71, an oscillation frequency adjusting variable inductance 72 connected in series to the coil 71, and a series circuit thereof. A capacitor 73, which forms a resonance circuit together with the coil 71 and the variable inductance 72, and inverters 74a, 74b,
And an oscillator composed of 74c. Coil 7
1 is provided in the developer circulation path in the tank of the developing device. The developer is configured to pass through the coil 71.

Here, since the carrier of the developer is a magnetic substance and the toner is a non-magnetic substance, the amount of the magnetic substance passing through the coil varies depending on the toner concentration of the developer passing through the coil. As the magnetic flux fluctuates and its permeability changes, the inductance of the coil also changes. As is well known, since the relationship between the toner concentration and the oscillation frequency can be approximated to a linear function, the toner concentration of this developer can be detected by detecting the characteristic value of the two-component developer.

The high-voltage drive power supply circuit 30 is a circuit for applying a predetermined high voltage to the transfer device 4 and the charging device 2. Charger 2,
The transfer device 4 is preferably a so-called corona charger or a corona transfer device that performs corona discharge, and is not limited to this as long as the discharge efficiency is uniform.

The microcomputer 80a controls the image forming means in sequence and has a built-in image forming program for executing the image forming process, and the image is generated by a start signal issued in response to the pressing of the copy button. The forming program is activated to execute the image forming process. The microcomputer 80a stores a toner concentration control program in the ROM, and activates the toner concentration control program during the image forming process, for example, as described later, so that the toner concentration detecting means 3 is detected.
Based on the signals from 1Y, 31M, 31C, and 31BK, the toner density of each color is controlled to be maintained at a predetermined value substantially constant.

The reading optical system 51 is composed of an illumination lamp (not shown) integrally formed with the first scanning mirror, and a second mirror (for example, a V mirror) which moves at a speed ratio of 1/2 of that of the first mirror. The original is scanned while the optical path length in front of the lens is always kept constant. As a result, the reading optical system 51 forms an image of the reflected light from the original image on the original glass on the light receiving portion of the solid-state image sensor. Reading optical system 5
Reference numeral 1 sends an output signal from the solid-state image pickup device to an image processing circuit (not shown) in the scanning optical system drive circuit 53.

The scanning optical system 52 is a fixed scanning system using a laser optical system equipped with a polygon mirror for rotating and scanning a laser from a semiconductor laser modulated by an image signal, an LED array, and liquid crystal.

The read scanning optical system drive circuit 53 is a circuit for controlling a mechanical system such as a polygon mirror, and the read optical system 51.
Is a circuit including an image processing circuit for color-processing the image signal from, for example, standard image density data that changes stepwise or continuously from 1.0 to 0 in optical reflection density is stored in the ROM, and this data is stored in this data. Based on this, a standard latent image is formed. In the present embodiment, the standard image density data corresponds to the optical reflection density of 0.8, but it is not limited to this and can be arbitrarily selected from 1.0 to 0. R
The OM corresponds to a standard image signal generation circuit.

The construction of one embodiment of the toner adhesion amount detecting device of the present invention will be described below with reference to FIGS. 4, 5 and 6.

FIG. 4 is a block diagram showing an embodiment of the toner adhesion amount detecting device of the present invention, FIG. 5 is a graph explaining the concept of the judgment level used in this embodiment, and FIG. 6 is this embodiment. It is a figure which shows schematic structure of the reflection density detection means.

As shown in FIG. 4, the toner detecting device comprises an optical reflection density detecting means 90 and a microcomputer 80 for making a control decision.

As shown in FIG. 6, the reflection density detecting means 90 accommodates a light emitting element 91 such as an LED and a light receiving element 92 for receiving the reflected light from the photosensitive drum 1 in a separately partitioned housing so that the reflection density detecting means 90 It is designed so that it does not receive the scattered light and the like. As shown in FIG. 4, the reflection density detecting means 90 has a light emitting element 91, a light receiving element 92, a power supply voltage V _CC in addition to the resistors R1 and R2, and supplies the output voltage of the light receiving element 92 to the microcomputer 80. .. When the photosensitive drum 1 rotates and the standard toner image comes to a position substantially opposite to the light emitting and light receiving elements 91 and 92, the light emitting element 91 emits light,
The light receiving element 92 outputs a voltage corresponding to the density of the standard toner image. Therefore, when a reference latent image formed as described below passes through the developing devices 3C, 3M, 3Y, a standard toner image is formed, the light emitting element 91 emits light, and light from the standard image side enters the light receiving element 92. .. The output of the light receiving element 92 becomes a voltage corresponding to the density of the standard toner image.

The microcomputer 80 is a control device for driving and controlling the image forming process elements to execute the image forming process as described above. Here, the toner adhesion amount is detected, that is, the color balance is determined. Y,
RO is a program for determining whether the toner adhesion amount of each of M and C is normal, that is, a color balance determination program.
A standard toner image of each color is sequentially superposed on the photosensitive drum 1 by sequentially executing a cycle of charging, exposure, and development processes by activating a color balance determination program stored in M as described later. To form a multi-layered toner image. Here, after the end of each cycle, that is, the standard toner image on the photosensitive drum 1 is changed to the developing device 3
Each time the toner passes through C, 3M, and 3Y, the amount of each color toner is detected by the output from the reflection density detecting means 90. That is, the amount of toner adhered for each color of Y, M, and C is obtained from the reflection density for each rotation of the photosensitive drum 1, and the situation of toner image formation for each color is recognized.

The color balance judgment program has a plurality of toner adhesion amount judgment level data shown in FIG. Here, the toner adhesion amount determination level will be described with reference to FIG.

The color balance determination data V _H is data corresponding to the maximum output voltage from the light receiving element 92, and is output when the light is totally reflected from the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 is a chromatic color such as blue,
It has a luster. The emission wavelength of the light emitting element 91 is
Common wavelengths having low spectral reflectance of the Y, M, and C color toners are preferable. Further, a wavelength having a low spectral reflectance common to two colors of Y, M, and C may be used, and the light receiving element 92 is preferably highly sensitive to that wavelength.

The toner adhesion amount determination data V ₀ is in the state where the amount of light reflected from the surface of the photosensitive drum 1 is 0.

In the first layer, one threshold value V _1TH1 is set, and V _{1 to} V _1TH1 are data corresponding to the case where the toner adhesion amount of the first color in the first layer is normal, that is, V _{1TH1 to VH.}
Is data corresponding to an abnormal toner adhesion amount of the first color on the first layer.

In the second layer, two thresholds V _2TH1 and V _2TH2
Is set to, V ₂ ~V _2TH1 is data corresponding to a normal case none of the toner adhesion amount of the second color in the toner adhering amount and the second layer of the first color in the first layer, V _2TH1 ~
V _2TH2 is data corresponding to the case where one of the toner adhesion amounts of the first and second colors is normal and the other is abnormal, and V _{2TH2 to VH} are the toner adhesion amounts of the first and second colors. Is data corresponding to an abnormal case.

In the third layer, three threshold _values V _3TH1 , V _3TH2 and V _3TH3 are set, and V _{3 to} V _3TH1 are 1 in the first layer.
The toner adhesion amount of the color, the toner adhesion amount of the second color on the second layer, and the toner adhesion amount of the third color on the third layer are data corresponding to the normal case, and V _{3TH1 to} V _3TH2
Is data corresponding to the case where only one of the toner adhesion amounts of the first, second and third colors is abnormal and the rest is normal,
V _{3TH2 to} V _3TH3 are data corresponding to the case where two of the toner adhesion amounts of the first color, the second color and the third color are abnormal and the remaining one is normal, and _{V3TH3 to VH} are the first color, the second color and Three
The data corresponds to the case where any of the toner adhesion amounts of colors is abnormal.

If the microcomputer 80 determines from the toner adhesion amount determination result that the toner adhesion amount is normal, the microcomputer 80 allows a so-called image forming process. If it is out of the allowable range, the charging condition, the image exposure condition, the process condition for forming an abnormal toner image at that time,
At least one of the developing conditions is controlled to restore the proper toner adhesion amount. Alternatively, it is characterized by forcibly consuming the toner in the developing device corresponding to the layer that has exceeded the allowable range.

In this embodiment, in the toner consumption step, the toner is forcibly consumed by adjusting the output voltage from the developing bias circuit 32. However, the present invention is not limited to this, and toner consumption can be performed by adjusting other electrostatic process conditions.

It should be noted that the toner adhesion amount determining means does not have to be used also as a microcomputer for executing the image forming process, and another microcomputer may be provided.
Further, although the toner adhesion amount determination method is described as software in the present embodiment, it is not limited to this, and it is easy for a person skilled in the art to implement it as hardware.

FIG. 7 is a flow chart showing various control operations of the image recording apparatus of this embodiment. First, when the power of the image recording apparatus is turned on (S-1), a pretreatment process is executed (S-2), and before the image formation is executed, the number of copies is a prescribed number, for example, 3000 × n ( n
Is an integer), and it is determined whether the number has reached (S-3). If the specified number of sheets has not been reached, image formation is executed (S
-4), it is judged whether or not the set number of copies has been reached (S-5), and this process is repeated until the number of copies reaches the set number. When the image formation of the set number of copies is completed, the post-processing step is executed (S-6) and the process is completed.

When the number of copies reaches the specified number in step (S-3), the electrostatic process condition control program (S-7) shown in FIG. 8 is entered.

First, the first charging process is performed (F-1),
The first image exposure process is performed (F-2), the first color development process is performed (F-3), and the first toner adhesion amount is detected (F-4). Here, it is determined whether the toner adhesion amount is normal or abnormal based on the toner adhesion amount determination described in FIGS. 4 and 5 (F-5). That is, the toner adhesion amount detection result is V
_{If 1 to} V _1TH1 , it is determined that the toner adhesion amount of the first color is normal, the determination result is stored in the memory (F-6), and the process proceeds to the second process. Toner adhesion amount detection result is _{V1TH1 to VH}
If so, it is determined that the first color is abnormal, and the process condition adjusting step is started (F-7), and the process control is performed so that the toner adhesion amount of the first color is appropriate. Then, the judgment result is stored in the memory (F-6), and the process proceeds to the second process.

Next, the second charging process (F-8), the second image exposure process (F-9) and the second color developing process (F-
10), the second toner adhesion amount detection (F-11) is performed. Here, it is again determined whether the toner adhesion amount is normal or abnormal (F-
12). That is, the toner adhesion amount detection result is V _{2 to} V
_If it is _2TH1 , both the first color and the second color are normal, so it is judged that the toner adhesion amount of the second color is normal, the judgment result is stored in the memory (F-13), and the process proceeds to the third process. If the toner adhesion amount detection result is V _{2TH1 to} V _2TH2 , it means that either one of the toner adhesion amounts of the first color and the second color is abnormal,
From the determination result stored in step (F-6), when the first color is abnormal, the second color is determined to be normal, the determination result is stored in the memory (F-13), and the process proceeds to the third process. On the contrary, when the first color is normal, the second color is judged to be abnormal, and the process condition adjustment process is started (F-14), and the process is controlled so that the toner adhesion amount of the second color is appropriate. Then, the judgment result is stored in the memory (F-1
3), go to the third process. If the toner adhesion amount detection result is V _{2TH2 to VH} , it means that both the first and second colors are abnormal. Therefore, it is determined that the second color is abnormal in step (F-12).
The process condition adjustment step is entered (F-14), and the process is controlled so that the amount of toner adhering to the second color is appropriate. Then, the judgment result is stored in the memory (F-1
3), go to the third process.

Finally, the third charging process (F-15), the third image exposure process (F-16), the third color developing process (F-17), and the third toner adhesion amount detection (F-18) are performed. .. Here, it is again determined whether the toner adhesion amount is normal or abnormal (F-19). That is, the toner adhesion amount detection result is V ₃
In the case of _{.about.V 3TH1} , all the first, second and third colors are normal, so that the toner adhesion amount of the third color is judged to be normal, and the image forming process of step (S-4) is started. If the toner adhesion amount detection result is V _{3TH1 to} V _3TH2 , the first color, the second color
This is a case where one of the toner adhesion amounts of the third color and the third color is abnormal, and the step (F-6) and the step (F-1).
From the judgment result stored in 3), when the first color or the second color is abnormal, it is judged that the third color is normal, and the step (S-
4) The image forming process is started, but when the first and second colors are normal, the third color is judged to be abnormal and the process condition adjusting process is started (F-20). The process is controlled so as to be appropriate. If the toner adhesion amount detection result is V _{3TH2 to} V _3TH3 , it means that any two of the toner adhesion amounts of the first color, the second color, and the third color are abnormal, and step (F-6) and step (F-13). ), The third color is judged to be normal when both the first and second colors are abnormal, and the image forming step of step (S-4) is started, but the first or second color is abnormal. When it is determined that the third color is abnormal, the process condition adjustment process is started (F-20), and the process is controlled so that the toner adhesion amount of the third color is appropriate, and then the step (S-
4) The image forming process starts.

FIG. 9 is a flowchart showing the operation of the electrostatic process condition control program (S-7) shown in FIG. 7, which is different from the embodiment shown in FIG. In this embodiment, standard images of the first color to the third color are successively formed on the photosensitive drum, the toner adhesion amount is detected each time, the result is stored, and whether the adhesion amount is abnormal or not is determined. Judgment is made to forcibly consume the toner in the abnormal developing device.

First, similarly to the embodiment of FIG. 8, the first charging process is performed for the first color (P-1), the first image exposure process is performed (P-2), and the first color developing process is performed (P). -3), the first toner adhesion amount is detected (P-4).
Here, it is not judged whether the toner adhesion amount is normal, but the detection result of the toner adhesion amount is stored (P-5). Next, the second charging process is performed for the second color (P-6), the second image exposure process is performed (P-7), and the second color development process is performed (P-8) to detect the second toner adhesion amount. The process is performed (P-9), and the detection result of the toner adhesion amount is stored (P-10). Next, the third charging process is performed for the third color (P-11), and the third image exposure process is performed (P-1).
2), the third color development process is performed (P-13), and the third
The toner adhesion amount is detected (P-14), and the detection result of the toner adhesion amount is stored (P-15). Subsequently, it is determined whether the detection result of the first toner adhesion amount stored in step (P-5) is abnormal (P-16). When the detection result of the first toner adhesion amount is not abnormal, the image forming process of step (S-4) of the image recording operation shown in FIG. 7 is started.
If the detection result of the first toner adhesion amount is abnormal, it is determined whether or not the detection result of the second toner adhesion amount stored in step (P-10) is abnormal (P-17). When the detection result of the second toner adhesion amount is not abnormal, the toner forced consumption cycle in the first color developing device is turned on (P-
19), the image forming process of step (S-4) is started. If the detection result of the second toner adhesion amount is abnormal, it is determined whether the third toner adhesion amount detection result stored in step (P-15) is abnormal (P-17). If the detection result of the third toner adhesion amount is not abnormal, the toner forced consumption cycle in the first and second color developing devices is turned on (P-20), and the image formation in step (S-4) is performed. Enter the process. If the detection result of the third toner adhesion amount is abnormal, the toner forced consumption cycle in the first, second, and third color developing devices is turned on (P-21), and the step (S-4). ) The image forming process is started. However in the embodiment of FIG. 9, the toner forced consumption cycle is assumed to be determined or let them be consumed toner amount of how much in advance.

FIG. 10 shows the concept of another determination level of the toner adhesion amount detection method.

In this example, when three color toners of Y, M, and C adhere to the drum, a larger amount of light is reflected from the surface where the toner is attached than the amount of reflected light from the surface of the drum where the toner is not attached. The amount of light is obtained, and as a result, the light receiving element 9
This is the case where the output of 2 becomes large as V _H <V _HH .
On the other hand, black toner is an example in which the amount of light reflected from the drum surface decreases as the toner adhesion amount increases, and decreases in the direction of V _H → V ₀ . These characteristics are the spectral reflectance of each color toner,
This is possible by selecting the spectral characteristics of the light emitting element and the light receiving element. In this case, the determination level for each color of the toner adhesion amount in FIG. 5 can be changed appropriately according to the output.

[0060]

As described above, according to the present invention, when a plurality of color toners are superposed on each other to form a multicolor image, the toner adhesion amount is detected every time one color is developed, and the toner adhesion amount is previously stored in the memory. It is judged whether it is normal or abnormal by comparing it with the stored reference data, and if it is abnormal, the process is controlled so that the proper toner adhesion amount is obtained, so that a multicolor image that always maintains good color reproduction can be obtained. Obtainable.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image recording apparatus to which a toner amount detection method of the present invention is applied.

FIG. 2 shows an internal configuration of a developing device used in the present invention.

FIG. 3 shows an electric circuit of an example of toner concentration detection means used in the present invention.

FIG. 4 is a block diagram showing a basic configuration of the present invention.

FIG. 5 is a graph illustrating the concept of the judgment level used in the present invention.

FIG. 6 is a schematic configuration diagram of an example of reflection density detecting means of the present invention.

FIG. 7 is a flowchart showing the operation of the present invention.

FIG. 8 is a flowchart showing the operation of the electrostatic process condition control program used in the present invention.

FIG. 9 is a flowchart showing another embodiment of the operation of the electrostatic process condition control program used in the present invention.

FIG. 10 is a graph illustrating the concept of another determination level used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3Y, 3M, 3C, 3BK Developing device 10 Motor driver 11 Encoder 31Y, 31M, 31C, 31BK Toner density detecting means 32 Development bias circuit 51 Scanning optical system 52 Scanning optical system 53 Scanning scanning optical system System drive circuit 80a, 80b CPU 90 Reflection density detection means

Claims (5)

[Claims] 1. When a plurality of reference latent images formed at the same position on a photoconductor are sequentially developed with color toners of different colors to form a reference color toner image in which toners of a plurality of colors are overlaid, A toner adhesion amount detection characterized by detecting the adhesion amount of the color toner each time one color toner is developed by the detecting means, and determining whether the toner adhesion amount is normal or abnormal by performing this detection a plurality of times. Method. 2. The toner adhesion amount detecting method according to claim 1, wherein the detecting unit is an optical unit. 3. When a plurality of reference latent images formed at the same position on a photoconductor are successively developed with color toners of different colors to form a reference color toner image in which toners of a plurality of colors are overlaid, the color When the amount of adhered color toner is detected by the detection means each time one color of toner is developed, and whether the amount of adhered toner is normal or abnormal is determined by performing this detection a plurality of times, and the amount of adhered toner is determined to be normal Is an image forming method characterized by permitting execution of a normal image forming process. 4. When the toner adhesion amount detection method according to claim 1 or 2 determines that the toner adhesion amount is abnormal, the toner image forming condition is adjusted by the toner determined to be abnormal. Image forming method. 5. When the toner adhesion amount detection method according to claim 1, 2, or 3 determines that the toner adhesion amount is abnormal, the toner consumption rate of the developing unit that loads the toner determined to be abnormal. An image forming method characterized by increasing the image quality.